Light source apparatus, lighting apparatus and projection display apparatus

ABSTRACT

A light source apparatus includes a lamp, an ellipsoidal mirror collecting a part of light radiated from a light transmission plane of the lamp, and a spherical mirror collecting another part of the light radiated from a light transmission plane not collected by the ellipsoidal mirror and reflecting it on the ellipsoidal mirror, in which a reflection plane of the ellipsoidal mirror and the reflection plane of the spherical mirror are in a form of non-rotation symmetry to an optical axis connecting a focal position F 1  corresponding to a source of luminescence of the lamp to a focal position F 2  of the light collected by the ellipsoidal mirror respectively. The distance between the reflection plane of the spherical mirror and the source of luminescence of the lamp is shorter than the distance between the source of luminescence and the focus of the light collected by the ellipsoidal mirror, and a part of the reflection plane of the ellipsoidal mirror is formed around the optical axis.

THIS APPLICATION IS A U.S. NATIONAL PHASE APPLICATION OF PCTINTERNATIONAL APPLICATION PCT/JP2004/005422.

TECHNICAL FIELD

The present invention relates to a light source apparatus having lightgenerating means and a concave mirror, a lighting apparatus and aprojection display apparatus.

BACKGROUND ART

In recent years, attention is being given to a projection displayapparatus using various light modulation devices as a large-screenprojection video apparatus. In the case of performing a large-screendisplay, brightness of a displayed image can be named as the mostimportant item.

Thus, attention is being given to a multi-lamp illumination system usingmultiple lamps and capable of improving optical output as the projectiondisplay apparatus. As for the brightness, it is important to illuminatethe light modulation device as an image display device with as littleloss of luminous fluxes radiated from the lamps as possible, that is, asefficiently as possible. For that reason, it is desirable to improveefficiency of the light source apparatus of collecting lamp radiationlight.

FIG. 11 shows a conventional multi-lamp optical system having two lightsource apparatuses configured by the lamp and concave mirror providedtherein. The light radiated from a light source apparatus 1 getsincident on a hollow rod integrator 2 made of glass poles or mirrorsglued together. It repeats total reflection inside the glass in the caseof the glass poles, or repeats reflection in the case of the type havingthe mirrors glued together. It is possible, by means of the reflectioninside the rod integrator 2, to create the luminous fluxes ofhomogeneous in-plane brightness on an emission opening plane of the rodintegrator 2. Furthermore, it is possible, with a relay lens 3 afterthis, to focus the luminous fluxes of high in-plane homogeneousness on alight modulation device 4 of performing an image display so as todisplay the image provided on a screen by a projection lens as the imageof which in-screen brightness is highly homogeneous.

Next, as for improvement in the efficiency of the conventional lightsource apparatus of collecting lamp radiation light, a basicconfiguration of the light source apparatus as a first conventionalexample is shown in FIG. 12 (refer to Japanese Patent No. 2543260 andJapanese Patent No. 3151734 for instance). In the case of this lightsource apparatus, the light radiated from light-transmitting planes 5 aand 5 b of a light-emitting portion 5 of the lamp is collected on afocus X by a first concave mirror 6 having an ellipsoidal orparaboloidal reflection plane form. The radiation light from thelight-transmitting planes 5 a and 5 b of the light-emitting portion 5 ofthe lamp not collected by the first concave mirror 6 is reflected on asecond concave mirror 7 consisting of a spherical mirror for instanceand having its reflection plane facing the reflection plane of the firstconcave mirror 6, and is then returned to the vicinity of thelight-emitting portion 5 of the lamp so as to be collected on the focusX by the first concave mirror 6.

Thus, the first concave mirror 6 and the second concave mirror 7 areused in a state of having their reflection planes facing each other, thesecond concave mirror 7 having the outermost diameter larger than theoutermost diameter in a vertical direction to an optical axis of thefirst concave mirror 6, that is, a straight line connecting aluminescence center 5 c of the light-emitting portion 5 to the focus X.The light radiated from the light-emitting portion 5 of the lamp isthereby taken in as much as possible so as to be collected by the firstconcave mirror 6.

The basic configuration of the light source apparatus as a secondconventional example is shown in FIG. 15 (refer to Japanese Patent No.2730782 and Japanese Patent No. 3350003 for instance). In the case ofthis light source apparatus, a light source 10 of the lamp is placed ona focus Y of an ellipsoidal mirror or paraboloidal reflecting mirror asa first concave mirror 8. The first concave mirror 8 is provided at anangle capable of reflecting all the radiation light from alight-transmitting plane 10 a of the light source 10. This light sourceapparatus coincides with the first conventional example in that thelight radiated from the light-transmitting planes 10 a of the lightsource 10 and reflected on the spherical mirror as a second concavemirror 9 is returned to the vicinity of the focus of the first concavemirror 8 and as much light radiated from a light-transmitting portion 10as possible is thus taken in together with the light radiated from thelight-transmitting plane 10 b and directly collected by the firstconcave mirror 8.

However, they are different in that the first conventional example hasthe opening of the second concave mirror 7 in a vertical plane againstan optical axis direction of the first concave mirror 6 whereas thesecond conventional example has the second concave mirror 9 placed in ahorizontal direction against the direction of the optical axis of thefirst concave mirror 8, that is, the straight line connecting aluminescence center 10 c of the light-emitting portion 10 of the lamp tothe focus Y.

As shown in FIG. 11, the conventional multi-lamp optical system has theconfiguration in which the light radiated from multiple light sourceapparatuses gets incident on the rod integrator 2 which is homogeneouslighting means. However, a transmissive/reflective liquid crystal ofdisplaying the image and the light modulation device called a DMD(Digital Micro-mirror Device) have a luminous flux incident angle rangecapable of substantially modulating the light and an image displayeffective area capable of displaying the image. For this reason, due tothe relation of Helmholtz-Lagrange which is a basic formula of imagingoptics, an output angle range of the light according to the size of anoutgoing side opening 2 b of the rod integrator 2 in an imaging relationwith the relay lens 3 is uniquely decided by the relay lens 3.

In this case, if the outgoing side opening and the incident side openingof the rod integrator 2 are of an equal size, the output angle range isequal to the incident angle range. If the outgoing side opening and theincident side opening are of different sizes, the incident angle rangeis in accordance with the size of the incident side opening induced bythe relation of Helmholtz-Lagrange, and so only the luminous flux withinthis angle range is projected onto the screen via the rod integrator 2,relay lens 3, light modulation device 4 and projection lens.

For this reason, in the case of the light source apparatus having asingle concave mirror 1 capable of collecting more lamp radiation light,the incident angle range of the rod integrator 2 is limited. Therefore,there is a problem that a distance between the concave mirror 1 and anincident side opening 2 a of the rod integrator 2 becomes long and anoptical spot size formed by the concave mirror 1 becomes large so thatan amount of light to be taken in by the opening of the rod integrator 2decreases.

As with the light source apparatus of the conventional multi-lampoptical system shown in FIG. 11, the light source apparatus of the firstconventional example shown in FIG. 12 is in a form of rotation symmetryto the optical axis of the first concave mirror, that is, the straightline connecting the luminescence center 5 c of the light-emittingportion 5 of the lamp to the focus X. It has a problem that, in the caseof forming a similar multi-lamp optical system, the amount of light tobe taken in by the opening of the rod integrator 2 decreases. It alsohas a problem that its outer shape becomes large.

The light source apparatus of the second conventional example shown inFIG. 15 is in a form of non-rotation asymmetry to the optical axis ofthe first concave mirror, that is, the straight line connecting theluminescence center 10 c of the light-emitting portion 10 of the lamp tothe focus Y. Its outer shape can be smaller than that of the firstconventional example. The luminous fluxes formed by collection of lightcan also be of non-rotation symmetry, and it is possible, even in themulti-lamp optical system of FIG. 11, to reduce the distance between thefirst concave mirror 8 corresponding to the first concave mirror 6 andthe incident side opening 2 a of the rod integrator 2.

However, the light source apparatus of the second conventional exampleshown in FIG. 15 has the following problem. The reflection plane havingthe second concave mirror 9 formed thereon reflects all the lightradiated from the light-transmitting plane 10 a as shown in FIG. 15.Nevertheless, all the reflected light is not collected by the firstconcave mirror 8, but a part of it is radiated outside so as to becomean impediment to light collection efficiency.

To collect all the reflected light of the second concave mirror 9 on thefocus Y, it is necessary to expand the reflection plane of the firstconcave mirror 8 by an equivalent of an area 150. However, this leads toa larger size of the light source apparatus so that the light collectionefficiency and the larger size of the light source apparatus will be ina trade-off relation.

The light radiated from a lamp 5 and directly reaching the first concavemirror 6 in an upper half in the light source apparatus of the firstconventional example of FIG. 12 is taken in by the second concave mirror9 in the light source apparatus of the second conventional example ofFIG. 15. In this case, the light reflected on the second concave mirror9 passes through the vicinity of the light-emitting portion 10 of thelamp again so as to get to the first concave mirror 8. In the case ofusing a metal halide lamp or a mercury lamp as the lamp, much of thelight passing through the light-emitting portion again is lost due tolight absorption and light scattering of light-emitting materials andmaterials configuring the lamp. Thus, it has a problem that the amountof luminous fluxes emitted to the focus Y is consequently reduced andoptical usable efficiency is lowered as the entire light sourceapparatus.

The present invention was made in order to solve these problems of theconventional examples, and an object thereof is to provide the lightsource apparatus of which optical usable efficiency is not lowered byminiaturizing it and the lighting apparatus and projection displayapparatus of higher efficiency and capable of miniaturization by havingthe light source apparatus.

DISCLOSURE OF THE INVENTION

The 1^(st) aspect of the present invention is a light source apparatuscomprising:

light generating means;

a first concave mirror of collecting a part of light radiated from thelight generating means; and

a second concave mirror of collecting another part of the light radiatedfrom the light generating means not collected by the first concavemirror and reflecting it on the first concave mirror,

wherein a reflection plane of the first concave mirror and a reflectionplane of the second concave mirror are in a form of rotational asymmetryto a reference axis connecting a source of luminescence of the lightgenerating means to a focus of the light collected by the first concavemirror respectively;

a distance between the reflection plane of the second concave mirror andthe source of luminescence is shorter than the distance between thesource of luminescence and the focus of the light collected by the firstconcave mirror; and

a part of the reflection plane of the first concave mirror is formedaround the reference axis.

The 2^(nd) aspect of the present invention is the light source apparatusaccording to the 1^(st) aspect of the present invention, wherein thefirst concave mirror has one or a plurality of quadratic surfaces as thereflection plane.

The 3^(rd) aspect of the present invention is the light source apparatusaccording to the 2^(nd) aspect of the present invention, wherein thequadratic surface of the first concave mirror is a part of anellipsoidal surface, and one of the focuses of the ellipsoidal surfacesubstantially coincides with the source of luminescence of the lightgenerating means while the other coincides with the focus of the lightcollected by the first concave mirror.

The 4^(th) aspect of the present invention is the light source apparatusaccording to the 1^(st) aspect of the present invention, wherein thesecond concave mirror has one or a plurality of quadratic surfaces asthe reflection plane.

The 5^(th) aspect of the present invention is the light source apparatusaccording to the 4^(th) aspect of the present invention, wherein thequadratic surfaces of the second concave mirror are a part of aspherical surface and a center of the spherical surface substantiallycoincides with the source of luminescence of the light generating means.

The 6^(th) aspect of the present invention is the light source apparatusaccording to the 1^(st) aspect of the present invention, wherein thereflection plane of the first concave mirror is located closer to thesource of luminescence than the reflection plane of the second concavemirror; and

the following relations are satisfied if, when a focusing angle of thefirst concave mirror is divided in two by a plane including thereference axis, a larger angle is α, a smaller angle is β, a maximumangle of the light radiated from the light generating means to the firstconcave mirror and the second concave mirror is γ, and the focusingangle of the second concave mirror is θ:α>β>0  (Formula 1)α+β≧180 degrees  (Formula 2)0<θ≦γ−β.  (Formula 3)

The 7^(th) aspect of the present invention is the light source apparatusaccording to the 1^(st) aspect of the present invention, wherein thereflection plane of the second concave mirror is located closer to thesource of luminescence than the reflection plane of the first concavemirror; and

the following relations are satisfied if, when a focusing angle of thefirst concave mirror is divided in two by a plane including thereference axis, a larger angle is α, a smaller angle is β, a maximumangle of the light radiated from the light generating means to the firstconcave mirror and the second concave mirror is γ, and the focusingangle of the second concave mirror is θ:α>β>0  (Formula 1)αβ≧180 degrees  (Formula 2)0<θ≦180 degrees.  (Formula 4)

The 8^(th) aspect of the present invention is the light source apparatusaccording to the 7^(th) aspect of the present invention, wherein thesecond concave mirror is placed in luminous fluxes formed by the firstconcave mirror.

The 9^(th) aspect of the present invention is the light source apparatusaccording to the 1^(st) aspect of the present invention, wherein

the light generating means is a lamp having a vessel body ofaccommodating the source of luminescence;

the vessel body has a spherical vessel portion of transmitting radiationlight from the source of luminescence and a pair of ends projecting fromthe spherical vessel portion; and

the pair of ends is provided around the reference axis.

The 10^(th) aspect of the present invention is the light sourceapparatus according to the 9^(th) aspect of the present invention,wherein the spherical vessel portion has a first opposed plane opposedto the reflection plane of the first concave mirror and a second opposedplane opposed to the reflection plane of the first concave mirror andthe reflection plane of the second concave mirror; and

the part of the reflection plane of the first concave mirror is at leastopposed to the second opposed plane.

The 11^(th) aspect of the present invention is a lighting apparatuscomprising:

the light source apparatus according to the 1^(st) aspect of the presentinvention; and

lens means placed at a position optically connecting with the focus ofthe light collected by the first concave mirror of the light sourceapparatus and converting the light emitted from the light sourceapparatus substantially to parallel light.

The 12^(th) aspect of the present invention is the lighting apparatusaccording to the 11^(th) aspect of the present invention, wherein thelens means is a rod integrator.

The 13^(th) aspect of the present invention is the lighting apparatusaccording to the 11^(th) aspect of the present invention, wherein thelens means is a lens array.

The 14^(th) aspect of the present invention is the lighting apparatusaccording to the 11^(th) aspect of the present invention, wherein thereare a plurality of the light source apparatuses placed so that therespective reference axes thereof coincide in the same plane; and

it further comprises light guiding means of guiding the light emittedfrom the plurality of light source apparatus to the lens means.

The 15^(th) aspect of the present invention is the lighting apparatusaccording to the 11^(th) aspect of the present invention, wherein theplurality of light source apparatus are placed so that the respectivereference axes thereof intersect at one point in space; and

the lens means is provided at a position corresponding to the one point.

The 16^(th) aspect of the present invention is the lighting apparatusaccording to the 15^(th) aspect of the present invention, wherein theplurality of light source apparatus are placed so that the secondconcave mirrors are mutually opposed.

The 17^(th) aspect of the present invention is the lighting apparatusaccording to the 15^(th) aspect of the present invention, wherein theplurality of light source apparatus are placed so that the first concavemirrors are mutually opposed.

The 18^(th) aspect of the present invention is a projection displayapparatus comprising:

the lighting apparatus according to the 11^(th) aspect of the presentinvention;

a light modulation device placed at a position optically connecting withthe lighting apparatus and modulating the light to form an opticalimage; and

a projection lens of projecting the optical image.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of describing an overview of a light sourceapparatus according to a first embodiment of the present invention;

FIG. 2 is a perspective view showing an overview configuration of thelight source apparatus according to the first embodiment of the presentinvention;

FIG. 3 is a sectional view showing an overview configuration of alighting apparatus according to the first embodiment of the presentinvention;

FIG. 4 is a sectional view showing an overview configuration of thelighting apparatus according to the first embodiment of the presentinvention;

FIG. 5 is a sectional view showing an overview configuration of aprojection display apparatus according to the first embodiment of thepresent invention;

FIG. 6 is a sectional view of describing an overview configuration andaction of the light source apparatus according to the first embodimentof the present invention;

FIG. 7 is a sectional view of describing an overview configuration andaction of the light source apparatus according to the first embodimentof the present invention;

FIG. 8 is a sectional view of describing an overview configuration ofthe lighting apparatus according to a second embodiment of the presentinvention;

FIG. 9 is a sectional view of describing an overview configuration ofthe lighting apparatus according to the second embodiment of the presentinvention;

FIG. 10 is a sectional view showing an overview configuration of aprojection display apparatus according to the second embodiment of thepresent invention;

FIG. 11 is a sectional view of an optical system using multipleconventional light source apparatuses;

FIG. 12 is a sectional view of the light source apparatus using multipleconcave mirrors shown as a first conventional example;

FIG. 13 is a schematic view of describing an effect of the opticalsystem using a mirror for a composite portion of multiple conventionallight source apparatuses;

FIG. 14 is a schematic view of describing an effect of the opticalsystem using the mirror for the composite portion of the multipleconventional light source apparatuses of the first conventional example;

FIG. 15 is a sectional view of the light source apparatus using themultiple concave mirrors shown as a second conventional example;

FIG. 16 is a sectional view of the optical system using the multipleconventional light source apparatuses;

FIG. 17 is a sectional view of describing an overview configuration ofthe lighting apparatus according to the second embodiment of the presentinvention;

FIG. 18 is a sectional view of describing an overview configuration ofthe lighting apparatus according to a third embodiment of the presentinvention; and

FIG. 19 is a sectional view of describing an overview configuration ofthe lighting apparatus according to the third embodiment of the presentinvention.

DESCRIPTION OF SYMBOLS

-   11 Lamp-   12 Ellipsoidal mirror-   13 Spherical mirror-   14 Optical axis-   111 Lamp light-emitting portion-   100 Light source apparatus-   101 Rod integrator-   F1 First focal position-   F2 Second focal position

BEST MODE FOR CARRYING OUT THE INVENTION

Hereunder, the embodiments of the present invention will be described byreferring to the drawings.

FIRST EMBODIMENT

Hereunder, a first embodiment of the present invention will be describedby referring to the drawings. FIG. 1 shows an overview configuration ofa light source apparatus according to the first embodiment.

This light source apparatus is configured by a lamp (an example of thelamp or light generating means of the present invention) 11, anellipsoidal mirror (an example of a first concave mirror of the presentinvention) 12 and a spherical mirror (an example of a second concavemirror of the present invention) 13.

The lamp 11 is configured by a lamp light-emitting portion 111 having asubstantially spherical vessel portion including a source ofluminescence positioned correspondingly to a focal position mentionedlater and generating light, and light transmission planes 111 a and 111b containing the source of luminescence and transmitting the lighttherefrom to the outside, and a pair of ends 111 c and 111 d includingelectrodes of the source of luminescence and having a form projectingfrom the lamp light-emitting portion 111. The vessel portion and ends111 c and 111 d of the lamp light-emitting portion 111 are integrallyformed from the same vessel body. As for the lamp 11, it is possible touse a xenon lamp having a light-emitting portion form as the source ofluminescence very close to a point source and capable of large opticaloutput, a metal halide lamp of high luminous efficiency, a mercury lamphaving an ultrahigh voltage in the lamp light-emitting portion (arctube) when lit up, and a halogen lamp.

Of the two focuses of the reflection plane of the ellipsoidal mirror 12,one is placed to coincide with the source of luminescence of the lamplight-emitting portion 111. Therefore, the light radiated from the lighttransmission plane 111 b and collected by the ellipsoidal mirror 12 isfocused on the outgoing opening side of the ellipsoidal mirror 12 so asto form an optical spot on the other focus. Here, if the position of thefocus coinciding with the source of luminescence of the lamplight-emitting portion 111 is a focal position F1 and the position ofthe focus at which the optical spot is formed is a focal position F2,the ellipsoidal mirror 12 is in a form of non-rotation symmetry to anoptical axis 14 thereof, that is, a reference axis connecting the focalposition F1 to the focal position F2. Furthermore, a part of thereflection plane of the ellipsoidal mirror 12 exists around the opticalaxis 14 shown in FIG. 1, and a further part thereof is formed to beopposed to the light transmission plane 111 a by going round to the backof a lamp 111.

The spherical mirror 13 is also in the form of non-rotation symmetry tothe optical axis 14, and the reflection plane thereof is opposed to thelight transmission plane 111 a of the lamp light-emitting portion 111 soas to cover a portion without the ellipsoidal mirror 12 in a rangereachable by radiation light therefrom. In FIG. 1, the center of thereflection plane of the spherical mirror 13 coincides with the focalposition F1. In short, the ellipsoidal mirror 12 can collect the lightradiated from the light transmission plane 111 b and the lighttransmission plane 111 a, and the spherical mirror 13 has aconfiguration capable of reflecting the light radiated from the lighttransmission plane 111 a.

Furthermore, a distance from the focal position F1 of the ellipsoidalmirror 12 to the reflection plane of the spherical mirror 13, that is, aradius of curvature R of the spherical mirror 13 is shorter than thedistance from a focal length of the ellipsoidal mirror 12 having thelamp light-emitting portion 111 to the focal position F2 of theellipsoidal mirror 12 at which luminous fluxes emitted from the lamplight-emitting portion 111 is collected by the ellipsoidal mirror 12 toform a spot, that is, an inter-focus distance L of the ellipsoidalmirror 12. The optical axis 14 is placed to penetrate the lamp 11, wherethe ends 111 c and 111 d are formed around the optical axis 14.

FIG. 2 shows a three-dimensional overview form of the light sourceapparatus. The sectional view of FIG. 1 is based on a line A–A′ of FIG.2. The line A–A′ is located in the same plane as the optical axis 14,and divides the light source apparatus in two from overhead.

An action of the light source apparatus shown in FIG. 1 will bedescribed. First, of the luminous fluxes emitted from the lamplight-emitting portion 111, the light reflected on the ellipsoidalmirror 12 is focused on the outgoing opening side of the ellipsoidalmirror 12 so as to form the optical spot on the focal position F2existing on the outgoing opening side of the ellipsoidal mirror 12. Inthis case, the luminous flux radiated from the source of luminescence ofthe lamp light-emitting portion 111 is formed by the light radiated fromthe light transmission plane 111 b and the light transmission plane 111a.

Of the luminous fluxes radiated from the lamp light-emitting portion111, the light radiated from the light transmission plane 111 a andreflected on the spherical mirror 13 is returned to the lamplight-emitting portion 111 of the lamp 11 again. It passes the vicinityof the lamp light-emitting portion 111, and is reflected thereafter onthe ellipsoidal mirror 12 so as to be focused on the second focus F2 ofthe ellipsoidal mirror 12 together with direct light from the lamplight-emitting portion 111.

Thus, the light source apparatus according to this embodiment has theconfiguration in which the ellipsoidal mirror 12 is in rotationasymmetry to the optical axis 14, where the light directly radiated fromthe lamp 11 is reflected to form the luminous fluxes in rotationasymmetry and the light radiated from the lamp 11 and not reflected onthe ellipsoidal mirror 12 is reflected on the ellipsoidal mirror 12again by the spherical mirror 13. Therefore, an amount of luminousfluxes close to the luminous fluxes in rotation symmetry is secured evenin the case of the luminous fluxes in rotation asymmetry.

Furthermore, the ellipsoidal mirror 12 is formed in rotation asymmetryto the optical axis 14, and the reflection plane is formed to go roundto the back of the lamp light-emitting portion 111 so as to directlycollect the light from the same light transmission plane as thatreflecting the light reflected on the spherical mirror 13. Thus, it isnot necessary for the spherical mirror 13 to reflect all the radiationlight from the light transmission plane 111 a as with the light sourceapparatus of the second conventional example of FIG. 15. It is therebypossible to prevent the reflected light from being radiated outsidewithout getting collected so as to obtain a sufficient amount ofluminous fluxes without changing a substantial size of the ellipsoidalmirror 12.

Furthermore, the light source apparatus according to this embodiment hasthe configuration in which the radius of curvature R of the sphericalmirror 13 is shorter than the inter-focus distance L of the ellipsoidalmirror 12, which has the effect of keeping the size of the light sourceapparatus minimum while securing a maximum amount of luminous fluxes.This has the following reason. To be more specific, it is sufficient,just for the sake of improving light collection efficiency, to providethe spherical mirror 13 at a position backed out until its reflectionplane substantially coincides with the focal position F2 as a convergentpoint of outgoing beams emitted from the ellipsoidal mirror 12 andfurther provide an opening of substantially the same size as a focusingspot at a position corresponding to the focal position F2 on thereflection plane of the spherical mirror 13. In this case, it ispossible to collect almost all the light emitted from the lamplight-emitting portion 111 with the spherical mirror 13 and theellipsoidal mirror 12 so as to obtain the maximum light collectionefficiency. However, the size of the light source apparatus itselfbecomes larger because the radius of curvature of the spherical mirror13 is fixed even if a focusing angle of the ellipsoidal mirror 12 ischanged.

For that reason, according to this embodiment, it is possible, byrendering the radius of curvature R of the spherical mirror 13 shorterthan the inter-focus distance L of the ellipsoidal mirror, to strike abalance between improvement in the light collection efficiency andminiaturization of the apparatus.

Next, a description will be given as to conditions of realizing thelight source apparatus in non-rotation symmetry to the optical axis 14having improved optical usable efficiency and in the form not enlargingthe size of the spherical mirror 13.

FIGS. 6 and 7 show sectional views on a vertical plane at which theangle for the spherical mirror 13 to take in the radiation light fromthe lamp 111 becomes the largest. To be more specific, the sectionalviews show the section at which the angle of viewing the sphericalmirror 13 from the light source 111 becomes the largest.

The following holds in the case where, of the focusing angles of theellipsoidal mirror 12 including the optical axis 14 and divided in twoat the plane orthogonal to the line A–A′ of FIG. 2, the larger one isangle α and the smaller one is angle β, and a maximum angle of the lightradiated from the lamp 11 is γ, and the range of the focusing angle ofthe spherical mirror is θ, and if the spherical mirror 13 is outside thereflected light of the ellipsoidal mirror 12 within the range scarcelyblocking the light reflected on the ellipsoidal mirror 12 as shown inFIG. 6, that is, if the reflection plane of the ellipsoidal mirror 13 isplaced closer to the light source 111 than the reflection plane of thespherical mirror 13.

(Formula 1)α>β>0  (1)(Formula 2)α+β≧180 degrees  (2)(Formula 3)0<θ≦γ−β  (3)

The reflection plane defined by the angle α reflects the radiation lightfrom the light transmission plane 111 b, and the reflection planedefined by the angle β reflects the light from the light transmissionplane 111 a.

It is desirable to satisfy the following in the case where the sphericalmirror 13 is formed on a surface of the vessel portion of the lamplight-emitting portion 111 or in proximity thereto within the rangescarcely blocking the light reflected on the ellipsoidal mirror 12 asshown in FIG. 7, that is, in the case where the reflection plane of thespherical mirror 13 is placed closer to the light source 111 than thereflection plane of the ellipsoidal mirror 12.

(Formula 1)α>β>0  (1)(Formula 2)α+β≧180 degrees  (4)(Formula 4)0<θ≦180 degrees  (5)As for the condition of FIG. 6, it is radius of curvature R of thespherical mirror 13<inter-focus distance L of the ellipsoidal mirror 12.

Here, an important point is that β is positive. This provides theconfiguration in which the reflection plane of the ellipsoidal mirror 12is vertically astride the optical axis 14 on both sides thereof in FIGS.6 and 7. Furthermore, it provides the configuration in which thereflection plane is opposed not only to the light transmission plane 111b but also to the light transmission plane 111 a by straddling the end111 c of the lamp 11. Thus, the ellipsoidal mirror 12 is verticallyastride the optical axis 14 on both sides thereof and the reflectionplane is opposed not only to the light transmission plane 111 b but alsoto the light transmission plane 111 a. It is thereby possible for theellipsoidal mirror 12 to directly collect the light from the lightsource 111 at a large angle. The spherical mirror 13 can be small-sizesince it has only to collect a small amount of the remaining light whichcannot be completely collected by the ellipsoidal mirror 12 out of thelight from the light transmission plane 111 a. Therefore, in this state,the light radiated from the light source 111 and heading for theellipsoidal mirror 12 without suffering a loss to be focused on thesecond focus F2 becomes the largest. This involves a relatively smallamount of light generating significant loss in the course of directlyheading for the spherical mirror 13, getting reflected, passing throughthe vicinity of the light source 111 and heading for the ellipsoidalmirror 12 until getting reflected on the ellipsoidal mirror 12 where itis focused on the second focus. Thus, the light collection efficiency ofthe light emitted from the entire light source apparatus is improved incomparison with the conventional examples without substantially changingthe size of the ellipsoidal mirror 12.

The formula (1) indicates the condition for the reflection plane of theellipsoidal mirror 12 to be in non-rotation symmetry to the optical axis14.

In the case where the relations of the formulas (2) and (4) are notsatisfied, the light reflected on the spherical mirror 13 reaches thearea in which the reflection plane of the ellipsoidal mirror 12 does notexist so that the optical usable efficiency cannot be improved.

The formulas (3) and (5) indicate the ranges in which the sphericalmirror 13 can collect the light.

The formula (3) is the case where the spherical mirror 13 is outside thereflection plane of the ellipsoidal mirror 12 as shown in FIG. 6.Therefore, it shows the range capable of taking in the radiation lightfrom the lamp 11 at the maximum and rendering the angle of the sphericalmirror 13 small.

In the case where the spherical mirror 13 is outside the reflectionplane of the ellipsoidal mirror 12, the size of the light sourceapparatus becomes larger than the case where it is in proximity to thevessel surface of the lamp 11 in the example of FIG. 7. As an advantage,however, there is reduction in density of the luminous fluxes emittedfrom the lamp light-emitting portion 111 and getting incident on thereflection plane of the spherical mirror 13 so that heat resistancerequired on the reflection plane can be alleviated.

The formula (5) is the case where, as shown in FIG. 7, the sphericalmirror 13 is on the lamp vessel surface substantially coinciding withthe light transmission plane 111 a or in proximity thereto and is placedin the luminous fluxes formed by the ellipsoidal mirror 12. Therefore,the size of the light source apparatus is hardly changed by an angularrange of the spherical mirror 13. Thus, it is desirable to provide theangular range placing more importance on the improved efficiency.

In the case of these configurations, it is possible to efficiently emitthe lamp outgoing beams radiated in rotation symmetry to the opticalaxis 14 from the ellipsoidal mirror 12 as the luminous fluxes innon-rotation symmetry to the optical axis 14.

FIG. 1 shows the case of using one piece of the spherical mirror 13. Inthe case of the ellipsoidal mirror in a form having some locations cutoff from the ellipsoidal mirror in rotation symmetry to the optical axis14, however, it is possible, by using multiple spherical mirrors, tocollect the radiation light from the lamp 11 reaching the area notcoverable by the ellipsoidal mirror even if the ellipsoidal mirror has acomplicated opening form so as to improve the optical usable efficiencyof the light source apparatus.

As shown in FIG. 3, it is possible to place a light source apparatus100, mirrors, a rod integrator 101 made of glass poles or mirrors gluedtogether, and optical means 102 such as a lens of this embodiment atpredetermined positions so as to obtain a lighting apparatus of thisembodiment of converting the light emitted from the light sourceapparatus 100 to predetermined approximately parallel light.

As shown in FIG. 4, it may also be the lighting apparatus using a lensarray 103 having multiple lenses two-dimensionally placed rather thanthe lighting apparatus using the rod integrator having the glass polesor mirrors glued together.

Furthermore, as shown in FIG. 5, it is possible to additionally providea field lens 104, a light modulation device 105 and a projection lens106 to the lighting apparatus 100 so as to obtain a projection displayapparatus of this embodiment.

It is possible to use as the light modulation device 105 a reflectivelight valve, a transmissive light valve, a mirror panel capable ofchanging a direction of reflection with small mirrors placed like anarray, and the light modulation device of an optical writing method.

Furthermore, while FIGS. 3, 4 and 5 show the lens as the optical meansof converting the radiation light from the light source apparatus toillumination light, it may also be the optical means using the mirrorsand a prism in addition to the lens or the optical system including anoptical component combining multiple lenses.

Furthermore, while FIG. 5 shows the configuration having just onetransmissive light valve as the light modulation device, it may also bethe configuration having multiple light modulation devices.

Furthermore, although it is not shown, it may be the configuration usingthe prism, filter and mirror capable of performing color separation andcolor composition.

As described above, according to the first embodiment, it is possible tohave the lamp 11, ellipsoidal mirror 12 and spherical mirror 13 andplace the spherical mirror at the position capable of collecting thelight not collectable by the ellipsoidal mirror in the form ofnon-rotation symmetry to the optical axis so as to obtain the lightsource apparatus of high efficiency and small size.

Furthermore, it is possible, by having such a light source apparatus ofhigh efficiency and small size, to render it brighter by using the lampof the same power and allow the same brightness by using the lamp oflower power so as to provide the lighting apparatus and projectiondisplay apparatus capable of pushing down power consumption.

The above description used the ellipsoidal mirror 12 as the firstconcave mirror. However, it may be any reflecting surface mirror havinga quadratic surface, where a reflecting surface mirror in the formcombining a parabolic mirror and multiple ellipsoidal mirrors may alsobe used. Furthermore, the first concave mirror is not limited to thequadratic surface but may also be formed by multiple planes or curvedsurfaces, such as a Fresnel mirror.

Furthermore, the spherical mirror is used as the second concave mirror.However, it may be any reflecting surface mirror having a quadraticsurface capable of efficiently reflecting lamp radiation light to theproximity of the lamp light-emitting portion, where the reflectingsurface mirror in the form combining the ellipsoidal mirror and multiplespherical mirrors may also be used. Furthermore, as with the firstconcave mirror, it is not limited to the quadratic surface but may alsobe formed by multiple planes or curved surfaces, such as the Fresnelmirror.

SECOND EMBODIMENT

Hereunder, a second embodiment of the present invention will bedescribed by referring to the drawings. FIGS. 8 and 10 show overviewconfigurations of the lighting apparatus and the projection displayapparatus according to this embodiment.

The light source apparatus 100 is the same as that in the firstembodiment, and so a description thereof will be omitted. As previouslydescribed, a multi-lamp optical system as shown in FIG. 11 uses multiplelight source apparatuses to be able to perform brighter illumination,combines the luminous fluxes emitted from each of the multiple lightsource apparatuses and has them incident on one piece of rod integratoror lens optical system to perform the illumination.

In the case of the optical system using a rod integrator 2 shown in FIG.11, it is necessary, for the sake of reducing the loss in the opticalsystem from the rod integrator 2 onward and improving the optical usableefficiency of the luminous fluxes emitted from the light sourceapparatuses, to render the focusing angle of the ellipsoidal mirror aslarge as possible and thereby collect more lamp radiation light with theellipsoidal mirror and further render a distance between the focalposition F1 (substantially coinciding with the light source of the lamp)and the focal position F2 (to be the convergent point of the luminousfluxes) of the ellipsoidal mirror 12 as small as possible so as torender the optical spots formed on an incident side opening 2 a of therod integrator 2 smaller.

In the case of placing multiple ellipsoidal mirrors having theirinter-focus distance reduced while rendering the focusing angle larger,it is known that the most efficient placement is that in the state ofhaving a part of the ellipsoidal mirrors physically interfering. As sucha configuration, there is the configuration already known as shown inFIG. 16, wherein a part of the concave mirror 1 of each light sourceapparatus is cut off in order to prevent the concave mirrors 1 ofmultiple light source apparatuses from physically interfering with oneanother. In this case, however, there is a problem that the lightcollection efficiency is lower only in a cut-off portion of the concavemirrors 1.

To avoid this problem, there is a configuration, as shown in FIG. 13, inwhich a pair of light source apparatuses is placed to have theirreflection planes opposed to each other and there is a mirror 200 placedimmediately anterior to the incident side opening 2 a of the rodintegrator 2 at an angle of guiding the luminous fluxes emitted frommultiple light source apparatuses 1 to the incident side opening 2 a ofthe rod integrator 2.

In the case of this configuration, there is no physical interference ofthe concave mirror 1 itself. If the mirror 200 is placed to reflect allthe luminous fluxes emitted from the concave mirror 1 onto the rodintegrator 2 side, however, there are the luminous fluxes not reflectedon the incident side opening 2 a due to the physics interference of themirror 200 so that the concave mirror 1 is not substantially used incertain areas (indicated by dotted lines in FIG. 13). In this case, theellipsoidal mirror has no interfering portion, and so the light incidenton a mirror interfering portion is not consequently used even though theellipsoidal mirror in rotation symmetry to the optical axis can beplaced.

Next, FIG. 14 is a diagram showing the configuration of a multi-lampoptical system using the light source apparatus of a conventionalconfiguration as in FIG. 12 as the light source apparatus of the opticalsystem of FIG. 13. In this case, there are areas of the first concavemirror 6 not substantially used (indicated by the dotted lines in FIG.13) as with the concave mirror of FIG. 13. There are the luminous fluxesfurther reflected on a second concave mirror 7 and then passing throughthe proximity of the light-emitting portion and getting incident on thearea of the first concave mirror 6 not substantially used in addition tothe luminous fluxes directly getting incident on the area of the firstconcave mirror 6 not substantially used from the lamp. Therefore, it hasthe problem that the optical usable efficiency is further lowered.

Furthermore, in the case of using the conventional light sourceapparatus as in FIG. 15 as a light source apparatus portion of FIG. 13,even the luminous fluxes which can be directly taken in by anellipsoidal mirror 8 are reflected on a spherical mirror 9 generating alight loss and then pass through the proximity of the light-emittingportion and get reflected on the ellipsoidal mirror 8. Therefore, theluminous fluxes emitted from the light source apparatus cannot be usedwith maximum efficiency.

The lighting apparatus according to the second embodiment of the presentinvention solves the above problems by using the light source apparatusof the first embodiment as the lighting apparatus.

FIG. 8 shows the lighting apparatus of the multi-lamp optical systemaccording to the second embodiment of the present invention using thelight source apparatus of the first embodiment of the present invention.

In the lighting apparatus, each light source apparatus 100 is placed sothat the optical axes 14 coincide in the same plane to be on the sameline in FIG. 8.

The light source apparatus 100 is placed to orient a smaller reflectionplane of the ellipsoidal mirror 12 toward an unused part of the portioninterfered with by the mirror 200 and have a spherical mirror 1positioned in the unused part. The mirror 200 is equivalent to lightguiding means of the present invention.

In the case of such a lighting apparatus, the radiation light from thelamp 11 incident on the spherical mirror 13 is returned to pass throughthe vicinity of the lamp light-emitting portion 111, and is emittedthereafter onto the mirror 200 side via the reflection plane of theellipsoidal mirror 12 capable of being used by the mirror 200 and therod integrator 101. Therefore, it becomes the luminous fluxes sufferingno loss after the rod integrator 101 so as to improve the optical usableefficiency of the luminous fluxes emitted from the light sourceapparatus.

To be more specific, on a specific section of the light source apparatus100 including a luminescence center (equivalent to the focal positionF1) on which the angle of viewing the spherical mirror 13 from theluminescence center is substantially the largest, the position ofproviding the reflection plane having the smallest angle (correspondingto an angle β shown in FIGS. 6 and 7) of the focusing angles of theellipsoidal mirror 12 to the optical axis 14 is placed to approximatelycoincide with the position in the luminous flux closest to an adjacentluminous flux emitted from one of the light source apparatuses when theluminous fluxes emitted from the two light source apparatuses 100 comeclose before getting incident on the rod integrator 101. Thus, thenumber of effective luminous fluxes directly collectable from the lamplight-emitting portion 111 by the ellipsoidal mirror 12 becomes thelargest. It is also possible, with the spherical mirror 13, to collectthe luminous fluxes from the lamp light-emitting portion 111 notcollectable by the ellipsoidal mirror 12.

As for this configuration, in the case of using the metal halide lamp orthe mercury lamp as the lamp 11, the loss occurs due to light absorptionand light scattering of light-emitting materials and materialsconfiguring the lamp 11. However, the light having passed through thevicinity of a luminous body without being absorbed or scattered, eventhough not all of the luminous fluxes reflected on the spherical mirror13, reaches the ellipsoidal mirror 12. Furthermore, the light collectionefficiency as the light source apparatus is improved because of theellipsoidal mirror 12 having the reflection plane formed in non-rotationsymmetry to the optical axis 14 and astride the optical axis 14.Therefore, the radiation light from the lamp 11 unusable so far can beused so as to improve the optical usable efficiency as the lightingapparatus.

It is also possible, of the luminous fluxes emitted from the lamplight-emitting portion 111, to obtain a larger number of luminous fluxesby direct light collection with the ellipsoidal mirror 12 as theshortest path and collect the remaining luminous fluxes via thespherical mirror 13 so as to significantly improve the light collectionefficiency.

It is also possible, as with the first embodiment, to render the radiusof curvature R of the spherical mirror 13 shorter than the focal lengthL of the ellipsoidal mirror 12 and thereby reduce the size of the lightsource apparatus 100 itself so as to miniaturize the entire lightingapparatus.

If the spherical mirror 13 is miniaturized, the focal length L of theellipsoidal mirror 13 can also be reduced. Therefore, it is possible toform a smaller optical spot for an incident side opening end 101 a ofthe rod integrator 101 so as to improve the light collection efficiencyfrom the rod integrator 101 onward.

Thus, according to this embodiment, it is possible to obtain thelighting apparatus capable of realizing both high optical usableefficiency and miniaturization.

FIG. 8 shows the example in which the light source apparatus 100 isplaced to orient a smaller reflection plane of the ellipsoidal mirror 12toward an unused part of the portion interfered with by the mirror 200and have a spherical mirror 1 positioned in the unused part. As shown inFIG. 17, however, it is also feasible to place each light sourceapparatus 100 so as to reverse positional relation between theellipsoidal mirror 12 and the spherical mirror 13. In this case, it isnecessary, for the sake of preventing the interference of the mirror200, to take a larger distance between the light source apparatus 100and the rod integrator 101. There is an advantage, however, that itbecomes easier to hold the spherical mirror 13 and place members such asan adjusting jig.

FIG. 8 shows the lighting apparatus using the rod integrator 101 made ofglass poles or mirrors glued together as an example. However, it mayalso be the lighting apparatus using the lens array 103 having multiplelenses two-dimensionally placed as shown in FIG. 9.

Furthermore, as shown in FIG. 10, it is possible to additionally providethe field lens 104, light modulation device 105 and projection lens 106to the lighting apparatus so as to obtain a projection display apparatusaccording to this embodiment.

It is possible to use as the light modulation device 105 the reflectivelight valve, the transmissive light valve and the light modulationdevice of an optical writing method.

Furthermore, while FIGS. 8, 9 and 10 show the lens as the optical meansof converting to the illumination light, it may also be the opticalmeans using the mirrors and prism in addition to the lens or the opticalsystem including an optical component combining multiple lenses.

Furthermore, while FIGS. 5 and 8 to 10 show the configuration havingjust one transmissive light valve as the light modulation device, it mayalso be the configuration having multiple light modulation devices.Furthermore, although it is not shown, it may be the configuration usingthe prism, filter and mirror capable of performing color separation andcolor composition.

As described above, according to the second embodiment, it is possible,on the lighting apparatus using multiple light source apparatuses havingthe lamp, ellipsoidal mirror and spherical mirror, to place thespherical mirror at the position capable of collecting the light notcollectable by the ellipsoidal mirror in the form of non-rotationsymmetry to the optical axis so as to obtain the light source apparatusof high efficiency.

Furthermore, it is possible, by thus having the light source apparatusof high efficiency, to render it brighter by using the lamp of the sameoutput and allow the same brightness by using the lamp of lower outputso as to provide the projection display apparatus capable of pushingdown the power consumption.

THIRD EMBODIMENT

FIG. 18 shows the configuration of the lighting apparatus according to athird embodiment of the present invention. In FIG. 18, the rodintegrator 101, a relay lens 102 and the light modulation device 105 arethe same as the conventional examples and the second embodiment. To bemore specific, it has the configuration in which the light sourceapparatus according to the first embodiment is used as the light sourceapparatus of the lighting apparatus of the conventional example shown inFIG. 11. In this case, the pair of light source apparatuses 100 isplaced to have their spherical mirrors 13 opposed to each other, and therod integrator 101 is placed at an intersection which is a point inspace at which the optical axes 14 of the light source apparatuses 100intersect.

The lighting apparatus of this embodiment has the same optical operationas the conventional example of FIG. 11. It uses the light sourceapparatuses of the first embodiment as the pair of light sourceapparatuses 100, and the luminous fluxes emitted from the light sourceapparatuses 100 directly reach the incident side opening end 101 a ofthe rod integrator 101.

When compared to the configuration of the second embodiment, the opticalaxes 14 of the light source apparatuses of this embodiment are obliqueas with the conventional examples, and so a problem remains, such asdifficulty in adjustment of optical axis fitting. It is possible,however, to radiate all the luminous fluxes in non-rotation symmetry tothe optical axis 14 to the rod integrator 101. Thus, as with theconventional example shown in FIG. 16, it is feasible, by using thelight source apparatus of a small inter-focus distance, to render thefocusing angle of the radiation light from the lamp 11 close to theangle of the light source apparatuses in rotation symmetry of theconventional example shown in FIG. 11 while rendering the optical spotformed by the rod integrator 101 smaller so as to obtain high opticalusable efficiency as the entire optical system.

It is also possible to simplify the number of parts and reduce the cost.

FIG. 18 shows the configuration of placing the pair of light sourceapparatuses 100 to have the spherical mirrors 13 opposed to each other.It is also possible, as shown in FIG. 19, to place them to have theellipsoidal mirrors 12 opposed to each other. In this case, it isfeasible, of the luminous fluxes incident on the rod integrator 101, tointensively have the luminous fluxes substantially almost parallel tothe optical axis of the rod integrator 101 incident on the incident sideopening end 101 a and increase a substantial amount of luminous fluxesfrom the rod integrator 101 onward in the lighting apparatus.Furthermore, there is also the advantage that it becomes easier to holdthe spherical mirror 13 and place the members such as an adjusting jig.

According to the above description, the ellipsoidal mirror is used asthe first concave mirror. However, it may be any reflecting surfacemirror having a quadratic surface, where a reflecting surface mirror inthe form combining the parabolic mirror and multiple ellipsoidal mirrorsmay also be used.

Furthermore, the spherical mirror is used as the second concave mirror.However, it may be any reflecting surface mirror having a quadraticsurface capable of efficiently reflecting the lamp radiation light tothe proximity of the lamp light-emitting portion, where the reflectingsurface mirror in the form combining the ellipsoidal mirror and multiplespherical mirrors may also be used.

As previously described, in the above embodiments, the lamp 11 is anexample of the lamp or light generating means of the present invention,the spherical vessel portion of the lamp light-emitting portion 111except the source of luminescence is an example of the spherical vesselportion of the present invention, the ends 111 c and 111 d are anexample of the pair of ends of the present invention, the lighttransmission plane 111 a of the lamp light-emitting portion 111 is anexample of a first opposed plane of the present invention, and the lighttransmission plane 111 b is an example of a second opposed plane of thepresent invention.

However, the light generating means of the present invention does notneed to be implemented as the lamp having the vessel body as in theembodiments. It may also be implemented by another light source such asa light-emitting diode. In the case where it is the lamp, it does nothave to be configured by the spherical vessel portion and the ends. Forinstance, it may also be in a substantially spherical or ellipsoidalform consisting only of the spherical vessel portion having the lighttransmission plane. In short, the light generating means of the presentinvention is not limited by its concrete configuration and form as longas its source of luminescence can form the focus of the first concavemirror and the reference axis of the present invention.

As described above, according to the present invention, it is possibleto provide the light source apparatus capable of realizing high opticalusable efficiency which is not lowered by miniaturizing it and alsoprovide the lighting apparatus and projection display apparatus of highoptical usable efficiency by having the light source apparatus.

1. A light source apparatus comprising: light generating means; a firstconcave mirror of collecting a part of light radiated from the lightgenerating means; and a second concave mirror of collecting another partof the light radiated from the light generating means not collected bythe first concave mirror and reflecting it on the first concave mirror,wherein a reflection plane of the first concave mirror and a reflectionplane of the second concave mirror are in a form of non-rotationsymmetry to a reference axis connecting a source of luminescence of thelight generating means to a focus of the light collected by the firstconcave mirror respectively; a distance between the reflection plane ofthe second concave mirror and the source of luminescence is shorter thanthe distance between the source of luminescence and the focus of thelight collected by the first concave mirror; a part of the reflectionplane of the first concave mirror is formed around the reference axis;and the second concave mirror is placed substantially outside luminousfluxes formed by having the light of the light generating meansreflected on the first concave mirror, wherein the reflection plane ofthe first concave mirror is located closer to the source of luminescencethan the reflection plane of the second concave mirror; and thefollowing relations are satisfied if, when a focusing angle of the firstconcave mirror is divided in two by a plane including the referenceaxis, a larger angle is α, a smaller angle is β, a maximum angle of thelight radiated from the light generating means to the first concavemirror and the second concave mirror is γ, and the focusing angle of thesecond concave mirror is θ:α>β>0  (Formula 1)α+β≧180 degrees  (Formula 2)0<≦γ−β.  (Formula 3)
 2. A light source apparatus comprising: lightgenerating means; a first concave mirror of collecting a part of lightradiated from the light generating means; and a second concave mirror ofcollecting another part of the light radiated from the light generatingmeans not collected by the first concave mirror and reflecting it on thefirst concave mirror, wherein a reflection plane of the first concavemirror and a reflection Diane of the second concave mirror are in a formof non-rotation symmetry to a reference axis connecting a source ofluminescence of the light generating means to a focus of the lightcollected by the first concave mirror respectively; a distance betweenthe reflection plane of the second concave mirror and the source ofluminescence is shorter than the distance between the source ofluminescence and the focus of the light collected by the first concavemirror; a part of the reflection plane of the first concave mirror isformed around the reference axis; and the second concave mirror isplaced in luminous fluxes formed by having the light of the lightgenerating means reflected on the first concave mirror, wherein thereflection plane of the second concave mirror is located closer to thesource of luminescence than the reflection plane of the first concavemirror; and the following relations are satisfied if, when a focusingangle of the first concave mirror is divided in two by a plane includingthe reference axis, a larger angle is α, a smaller angle is β, a maximumangle of the light radiated from the light generating means to the firstconcave mirror and the second concave mirror is γ, and the focusingangle of the second concave mirror is θ:α>β>0  (Formula 1)α+β≧180 degrees  (Formula 2)0<θ≦180 degrees.  (Formula 4)
 3. The light source apparatus according toclaim 1 or claim 2, wherein the first concave mirror has one or aplurality of quadratic surfaces as the reflection plane.
 4. The lightsource apparatus according to claim 3, wherein the quadratic surface ofthe first concave mirror is a part of an ellipsoidal surface, and one ofthe focuses of the ellipsoidal surface substantially coincides with thesource of luminescence of the light generating means while the othercoincides with the focus of the light collected by the first concavemirror.
 5. The light source apparatus according to claim 1 or claim 2,wherein the second concave mirror has one or a plurality of quadraticsurfaces as the reflection plane.
 6. The light source apparatusaccording to claim 5, wherein the quadratic surfaces of the secondconcave mirror are a part of a spherical surface and a center of thespherical surface substantially coincides with the source ofluminescence of the light generating means.
 7. The light sourceapparatus according to claim 1 or claim 2, wherein the light generatingmeans is a lamp having a vessel body of accommodating the source ofluminescence; the vessel body has a spherical vessel portion oftransmitting radiation light from the source of luminescence and a pairof ends projecting from the spherical vessel portion; and the pair ofends is provided around the reference axis.
 8. The light sourceapparatus according to claim 7, wherein the spherical vessel portion hasa first opposed plane opposed to the reflection plane of the firstconcave mirror and a second opposed plane opposed to the reflectionplane of the first concave mirror and the reflection plane of the secondconcave mirror; and the part of the reflection plane of the firstconcave mirror is at least opposed to the second opposed plane.
 9. Alighting apparatus comprising: the light source apparatus according toclaim 1 or claim 2; and lens means placed at a position opticallyconnecting with the focus of the light collected by the first concavemirror of the light source apparatus and converting the light emittedfrom the light source apparatus substantially to parallel light, whereinthe light source apparatus is one of a plurality of light sourceapparatus which are placed so that the respective reference axes thereofintersect at one point in space; and the lens means is provided at aposition corresponding to the one point.
 10. The lighting apparatusaccording to claim 9, wherein the lens means is a rod integrator. 11.The lighting apparatus according to claim 9, wherein the lens means is alens array.
 12. The lighting apparatus according to claim 9, whereinthere are a plurality of the light source apparatuses placed so that therespective reference axes thereof coincide in the same plane; and itfurther comprises light guiding means of guiding the light emitted fromthe plurality of light source apparatus to the lens means.
 13. Thelighting apparatus according to claim 9, wherein the plurality of lightsource apparatus are placed so that the second concave mirrors aremutually opposed.
 14. The lighting apparatus according to claim 9,wherein the plurality of light source apparatus are placed so that thefirst concave mirrors are mutually opposed.